Phase and Mineralogical Transformations of Opal Clays in the Production of Ceramic Bricks

Abstract:

Due to a wide range of studies, it has been established that siliceous clays can be an alternative source of raw materials for the production of various types of structural ceramics. Their wide occurrence contributes to their usage in industrial production. Siliceous clays have a specific mineralogical composition and were previously considered only as an additive to increase the plasticity of the main raw material. The chemical composition, properties of green and fired siliceous clays of the Malchevsky deposit has been studied in detail. They consist of 67-70% silica, 13-15% alumina, and 1-3% alkaline earth oxides. The main minerals are opal silica and beidellite. These thermographs confirm the presence of montmorillonite, zeolites, mica and hydromica, opal silica and quartz. It is established that siliceous clays belong to the groups of medium dispersed and highly plastic raw materials. Despite the increased molding moisture and great shrinkage, they are moderately sensitive to drying and allow you to get molding masses with high binding property. At the firing temperature of 1000-1020 ° C, the brick is free from defects, the strength grade is M200-250, and the frost resistance is F75. There are X-ray data of siliceous clays burned at temperatures of 900, 950, 1000, 1050, 1100° C. Significant phase transformations become noticeable at a temperature of 1000° C, when the process of transition of amorphous opal silica to cristobalite begins. At 1050° C, the formation of a glass phase begins. The results obtained suggest that the main phases of the fired material based on siliceous clays are quartz and cristobalite with a low degree of structural perfection and the formation of the microstructure occurs in the interval 1000-1100° C. So, siliceous clays can be considered as the main and additional material for the production of various types of structural ceramics.

• Periodical: Materials Science Forum (Volume 974)
• Pages: 162-167
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.974.162
• Online since: December 2019
• Authors: J. Bozhko*, Kira Lapunova, Marina Orlova, Yana Lazareva
• Keywords: Cristobalite, Phase Transformations, Quartz, Silica, Siliceous Clays

References

[1] V.D. Kotlyar, D.I. Bratskii, Material structure and ceramic properties of a clay opoks. Engineering herald of the Don region. 14 (4) (2014) 47–59. (In Russian).

[2] V.D. Kotlyar, Siliceous opoks rocks of Krasnodar Krai region– perspective raw materials for wall ceramics, Construction Materials. 4 (2010) 34–36. (In Russian).

[3] A.G. Bondariyk, V.D. Kotlyar, Phase transformations when roasting opoks with carbonate additives by production of wall ceramics, Construction Materials. 12 (2009) 24–27. (In Russian).

[4] V.D. Kotlyar, Wall ceramics on the basis of siliceous opal–kristobalit of rocks – opoks, Rostov–on–Don, Rostov state University of civil engineering, (2011).

[5] V.D. Kotlyar, Classification siliceous the opoks of rocks as raw materials for production of wall ceramics, Construction Materials. 3 (2009) 36–39. (In Russian).

[6] V.D. Kotlyar, K.A. Lapunova, Features of physical and chemical transformations when roasting opoks raw materials, Construction Materials. 5 (2016) 40–42. (In Russian).

[7] A.G. Bondariyk, V.D. Kotlyar, Wall ceramics on a basis the opoks of siliceous–carbonate and artificial siliceous and carbonate compositions. Bulletin of the higher educational institutions. Construction. 7 (2010) 18–24. (In Russian).

[8] V.D. Kotlyar, K.A. Lapunova, Technological features of opoks as raw materials for wall ceramics, Bulletin of the higher educational institutions. Construction 11-12 (2011) 25-31. (In Russian).

[9] K.A. Lapunova, V.D. Kotlyar, Technology and design of front products of wall ceramics on the basis of siliceous the opoks of rocks, Rostov–on–Don, Rostov state University of civil engineering. (2014).

[10] V.S. Gorshkov, V.G. Savel'ev, Physical chemistry of silicates and other refractory connections, Higher school, Moscow, (1988).

[11] B.V. Talpa, V.D. Kotlyar, U.V. Terekhina, Assessment siliceous the opoks of rocks for production of a ceramic brick, Construction Materials. 12 (2010) 20–22. (In Russian).

[12] V.D. Kotlyar, B.V. Talpa, G.A. Kozlov, A.A. Belodedov, Siliceous rocks of the lower Don and perspective ways of their use in production of construction materials. Scientific Ideas of the Caucasus. 6 (2004) 97–104. (In Russian).